Bearings and method of manufacture



June 1967 1.. s. SULLIVAN, JR 3,328,101

BEARINGS AND METHOD OF MANUFACTURE Original Filed Dec. 10, 1959 5Sheets-Sheet 1 lie 71'? BEFORE AFTER L v M01 DING M0 DING IN V EN TOR.

[e0 5. Su/lz'mn, J1: BY v H15 ATTORNEY June 27, 1967 L. S. SULLIVAN, JR

BEARINGS AND METHOD OF MANUFACTURE 5 Sheets-Sheet Original Filed Dec.10, 1959 INVENTOR.

160 5: Sullim BY 1913 ATTOR/Viy June 1967 L... s. SULLIVAN, JR

BEARINGS AND METHOD OF MANUFACTURE 5 Sheets-Sheet Original Filed Dec.10, 1959 INVENTOR.

Zea 5. Sullivan H15 ATTORNEY June 27, 1967 L 5 su v N, JR 3,328,101

BEARINGS AND METHOD'OF MANUFACTURE Original Filed Dec. 10, 1959 5Sheets-Sheet I I .700 50c INVEN TOR.

50 5. Sullivan, Jr.

HIS A 770171166) June 27, 1967 L. s. SULLIVAN, JR 3,328,101

BEARINGS AND METHOD OF MANUFACTURE I Original Filed Dec. 10, 1959 5Sheets-Sheet s I INVENTOR 0 I f [Yea 51 80/11 Van, Jr.

United States Patent O 3,328,101 BEARHNGS AND METHUD OF MANUFACTURE LeoS. Sullivan, Jr., Dayton, Ohio, assignor to General Motors Corporation,Detroit, Mich., a corporation of Delaware Original application Dec. 10,1959, Ser. No. 858,656, now Patent No. 3,097,060, dated July 9, 1963.Divided and this application May 28, 1965, Ser. No. 459,751

2 Claims. (Cl. 308-438) This is a divisional application based uponcopending parent application S.N. 858,656Sullivan filed Dec. 10, 1959,now Patent 3,097,060-Sullivan issued July 9, 1963 and another divisionalapplication S.N. 255,123-Sullivan filed Jan. 30, 1963, now Patent3,211,483Sullivan issued Oct. 12, 1965.

This invention relates to bearing surfaces and particularly toproduction thereof in a molding procedure adapted simultaneously toproduce a cured and bonded combination of resilient as well aswear-resistant materials together 'for noise isolation and eliminationof lubrication problems.

An object of this invention is to provide a new and improved bearingsurface relative to molded elastomeric material such as natural andsynthetic rubber that is simultaneously cured and bonded together with awoven preform having a fluorine containing synthetic resin surface forwear resistance resiliently backed by the elastomeric material.

Another object of this invention is to provide a molding procedure forbushing and ball joint bearing surfaces and the like wherein there aresteps of placing a preform of polytetrafluoroethylene woven on an innerbearing surface backed by phenolic-impregnated cotton relative to a moldpart such as a mandrel as well as a mold base, filling a cavity betweenthe preform and an outer metal portion with elastomeric rubber-likematerial under pressure as well as in a semi-fluid condition andsimultaneously curing as well as bonding the elastomeric materialtogether with the preform into a predetermined contour ofpolytetrafluoroethylene surface weaving mechanically locked againstrotation relative to the phenolic-impregnated cotton that adheres firmlyto the rubber-like materal.

Another object of this invention is to provide a bushing and procedurefor making the same whereby a metal sleeve is placed into a portion of amold, a woven tubular preform is fitted concentrically thereto relativeto a mandrel immediately adjacent to a fluorine containing syntheticresin surface on a phenolic-impregnated fibrous backing construction ofthe preform, forcing uncured elastomeric material in a semi-fluidcondition as a filling in space between the preform and metal sleeve sothat the preform including the fluorine containing synthetic resinsurface conform to mandrel shape that can be cylindrical as well asthreaded, simultaneously curing as well as bonding the elastomericmaterial under conditions such as predetermined heat and pressure intoadhesion relative to both the metal sleeve and phenolic-impregnatedfibrous backing of the preform removable from the mold portion andmandrel as a unitary assembly.

A further object of this invention is to provide a permanentlylubricated ball joint and socket structure including a combination ballseat and elastomeric compression means integral with an annular sealinglip portion adapted to engage a socket body adjacent to where a coverfits complementary thereto at a location laterally outside a partiallyspherical bearing surface of polytetrafluoroethylene woven relative to aphenolic-impregnated fiber backing which is bonded and curedsimultaneously with the elastomeric means in a unitary structure.

Another object of this invention is to provide a permanently lubricatedball joint and socket structure having a 3,323,101 Patented June 27,1967 partially spherical preform of phenolic-impregnated cotton as abacking for polytetrafluoroethylene fibers woven in locking engagementtherewith to be engageable by the ball and resiliently urged intoengagement therewith by a rubber-like elastomeric materialsimultaneously cured and bonded therewith and having an annular sealinglip portion integral therewith for resiliently engaging a casing of theball joint and socket structure in a location adjacent to where a coverfits thereto such that an effective dirt seal, for example, is provided.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein preferred embodiments of the present invention areclearly shown.

In the drawings:

FIGURE 1 is a composite elevational view of before and after structuralrelation in a molding procedure in accordance with the presentinvention.

FIGURE 1-a is a partially sectioned elevational view of a bushingassembly made in the procedure indicated for FIGURE 1.

FIGURE 1-!) is an end sectioned view of the bushing assembly taken alongline B--B in FIGURE -1a.

FIGURE 2 is a cross-sectional elevational view of a bushing beingmanufactured by procedure in accordance with the present invention.

FIGURE 2-a is an elevational cross-sectional view of the bushing shownin FIGURE 2.

FIGURE 2-b is an end view of the bushing of FIG- URE 2-0.

FIGURE 3 is a sectioned elevational exploded view of a ball joint andsocket assembly including components made in accordance with the presentinvention.

FIGURE 4 is a cross-sectional elevational view of a ball joint andsocket assembly including parts of FIG- URE 3.

FIGURE 4-41 is an end view of a component in accordance with the presentinvention for the ball joint and socket assembly of FIGURE 4.

FIGURE 4b is a cross-sectioned elevational view taken along line B-B inFIGURE 4-a.

FIGURE 4-0 is an end view of a cover for the ball joint and socketassembly of FIGURE 4.

FIGURE 4-d is a cross-sectioned elevational view taken along line DD inFIGURE 4-0.

FIGURE 4-e is a fragmentary enlarged sectional view of a portion ofFIGURE 4-d.

FIGURE 5 is a partially sectioned view of a pivot assembly including abushing and sealing member in accordance with the present invention.

FIGURE 5-a is a cross-sectioned elevational view of a seal with abearing surface portion manufactured in accordance with the presentinvention.

Efforts are continually being made to improve pivotal joints such as forsuspension systems on motor vehicles. Use of elastomeric materials forbushings as well a ball joint and socket structures has been known butinvolves a disadvantage due to wear and deterioration or aging of theelastomeric material, for example. Some synthetic resins having arelatively high fluorine content such as polytetrafluoroethylene(Teflon) have considerable wear resistance and are particularlyadvantageous for use in pivotal structures because they possess hightemperature and chemical stability as well as resistance to penetrationof water and water vapor. However, synthetic resin material such aspolytetrafiuoroethylene cannot be readily and satisfactorily bonded toitself or other material such as metals, elastomers, synthetic resinsand the like. For purposes of noise isolation, it is desirable toprovide a bearing surface of wear resistant synthetic resin and inaddition to have a supporting part integrally joined and simultaneouslyformed therewith as made of a wide variety of materials, particularly anelastomeric material, such as natural rubber, butadiene-acrylonitrilecopolymer, butadiene-styrene copolymer, polychloroprene as well asthermosetting and thermoplastic resins such as phenolic and vinyl resinscompatible for bonding relative to a metal as well as an elastomericmaterial without any adhesive layer therebetween. The use of a suitableadhesion cement involves inconvenience as well as danger of separationor misalignment of the bearing surface relative to a supporting partwithout benefit of a resilient backing as provided by elastornericmaterial useful to compress material forming the bearing surface forenhancing engagement thereof relative to a pivotal member such as a balljoint or pivotal suspension pin mounting. Benefits of this elastomericmaterial backing are lost when a synthetic resin surface alone isprovided for bearing purposes relative to a ball joint or pivot pin. Inaccordance with the present invention, there is provided a procedurewhereby a single cure operation is eflective upon elastomeric materialas well as a phenolic-impregnated fabric for curing and setting bothsimultaneously. The rubber-like elastomeric material as well as apreform of phenolic-impregnated fabric to which Teflon thread ismechanically woven assures finishing and joining in a single operationto provide a resiliently backed, wear-resistant bearing surface relativeto which noise is isolated by the elastomeric material and lubricationthereof is not a necessity. Use of phenolic resin alone as a backing forTeflon results in a hard and rigid structure which retains its shape butwhich does not afford noise isolation whereas use of an elastomericmaterial such as rubber and the like as a backing forphenolic-impregnated fabric to which the Teflon is woven along a bearingsurface results in a resilience and elasticity which is particularlydesirable and inexpensive to attain in accordance with the presentinvention involving a single curing operation effective upon bothphenolic resin as Well as rubber-like elastomeric materialsimultaneously.

FIGURE 1 illustrates a molding sequence in accordance with the presentinvention for forming a vehicle suspension system control arm bushinggenerally indicated by numeral 10. The bushing per se is illustrated inviews of FIGURES 1-a and 1b and includes only an outer cylindrical metalmember Itlm having a hexagonal-shaped hub portion h integral therewithalong one end thereof and provided with a plurality of threads or athreaded portion 1th as visible in FIGURE l-a. Apparatus for carryingout procedure in accordance with the present invention includes a moldbase 122: provided with a mold core 120 having a threaded end portionI121. visible in FIGURE 1. Complementary to the mold base 12b there is atransfer pot 12p or complementary cover portion adapted to fit adjacentto a space 12s into which the metal member or sleeve 10m is positionedafter a woven tubular preform generally indicated by numeral 14 isplaced on the mold core 120. The first step of placing the preform 14 onthe mold core involves having a fibrous portion 14 impregnated withuncured phenolic resin indicated such as at 14p relative to textilefabric such as cotton that is interwoven with synthetic thread ofpolytetrafluoroethylene 14.1 as a bearing surface along an innerperiphery of the preform 14. The left portion of the composite view ofFIGURE 1 illustrates this preform in an uncured condition as looselyspaced from the metal member 10m located radially outside thereof with agap 14g therebetween. The mold core has an annular recess ltlr intowhich one end of the preform 14 fits as illustrated in a partiallysectioned portion of FIG- URE 1. With both the metal bushing member16111 and woven tubular preform 14 concentrically placed relative toeach other over the mold core 120 that is positioned in the mold base12]) in a location inside the bushing metal member 10111, the transferpot 12p is positioned in complementary relation to the mold base. Thetransfer pot includes a cavity C relative to which a plunger P isslidable as a piston to transmit force represented by arrows F.

The left half of the view of FIGURE 1 represents relationship of partsbefore molding. The right-hand portion of the view of FIGURE 1represents production of a bearing surface in a molding procedure inaccordance with the present invention after molding. The cavity C has amascerated phenolic material placed therein for displacement in asemi-fluid state under pressure as can be applied manually orhydraulically relative to the plunger P for effecting transfer ofsemi-fluid mascerated phenolic represented generally by numeral 16 intothe space of numeral 14g that is now completely filled with themascerated phenolic in a semi-fluid state. Concurrently with the step offilling this space 14g, there is a transferring of force or pressurethrough the mascerated phenolic to an outer periphery of theTefloncotton preform causing the preform to conform to the shape of themold core including threaded portion 12:. In accordance with the presentinvention, pressure is maintained on the mold plunger which, togetherwith heat, effects curing simultaneously of both the mascerated phenolicmaterial 16 as well as the phenolic-impregnated cotton or fabric 141.After this single curing step for both the mascerated phenolic andphenolic impregnated cotton of the preform, the Teflon fibers formingthe bearing surface Mt assume a rigid setting which is now firmly backedand permits the mold to be opened and the bushing including the metalmember 10m, the cured mascerated phenolic material 16 as well as thepreform 14 to be unthreaded from the threaded portion ll2t of the moldcore 12c. Due to presence of the synthetic fiber such as Teflon, thereis no lubrication necessary in service and a permanently threadedportion T is provided relative to the rigid bushing structure. It is tobe noted that locking of the mascerated phenolic relative to an innerperiphery of the metal member 10m is enhanced by having the metal memberprovided with a plurality of internal grooves into which flange portions16 of the phenolic are molded in complementary relationship thereto.Provision of these flange portions 16 assures against axial separationof the metal member 10m relative to the molded material and preformcured in a single operation. As better seen in the view of FIGURE l-b,the flange portions 16 preferably fit int-o keyway-type recesses 10k inthe metal member 10m such that a locked relationship between the moldedmaterial and metal member is established to prevent rotative movementtherebetween as well as longitudinal separation as indicated earlier.The keyway-like recesses 10k also serve as slots to permit passage ofsemi-fluid mascerated phenolic material during transfer thereof underpressure from the cavity C into the annular space 14g.

Another molding sequence is illustrated in the view of FIGURE 2 showinga bottom half of a mold 22b and a complementary top half or portion 22padapted to abut against one end of the bottom portion 22b of the mold.The molding apparatus further includes a plunger 22F used fortransmission of force which can be mechanically or hydraulically appliedrelative to one end thereof. In any event, the plunger 22F transmits theforce to an elastomeric material such as rubber and the like in a pot orchamber portion 22C and the elastomeric material is forced through asprue or passages 22X to fill space between an annular outer metalsleeve or cylinder 22m of a bushing means generally indicated by numeral22, An annular end 222 of this bushing means 22 abuts against aknock-out ring or annular member 22k located concentrically along anouter periphery of a mandrel M secured to the bottom half of the mold bya bolt means B. To aid in disassembly of the bushing bolted inaccordance with the present invention, the bottom half of the mold 22bis provided with knock-out holes 2211 which are longitudinally inalignment with the knock-out ring 22k. The molding sequence for theprocedure indicated by FIG- URE 2 includes the steps of placing themetal annular member 22m into the bottom half of the mold and thenplacing a woven tubular preform generally indicated by numeral 24 on themold mandrel M. The preform construction includes a Teflon thread wovenas a bearing surface 241 along an inner surface backed byphenolicimpregnated fibrous material such as cotton indicated by numeral24f visible in views of FIGURES 2, 2-0 and 2-1). After placing thepreform 24 on the mold mandrel M, there is a step of locating the top ofthe mold in place relative to the bottom of the mold, and uncuredelastomeric material such as rubber and the like is filled into the moldpot or cavity 22C. Then the plunger 22F is placed in position andsubjected to pressure for displacing the uncured rubber from the pot orcavity 22C into a gap between the preform means 24 and bushing means 22.During mold closure with the plunger exerting pressure relative to theuncured rubber, the rubber, for example, or other elastomeric materialbecomes semi-fluid and passes through the passages of the sprue forfilling the gap between the preform and inner surface of metal sleeve ormember 22m. There is a building up of hydraulic pressure and forcestransmitted through the semifluid rubber-like material such that thepreform 24 conforms to mandrel size. Preferably, the surface of metalmember 22111 adjacent to the elastomeric material represented generallyby numeral 26 is treated for rubber adhesion prior to molding such thatthe elastomeric material bonds to the metal member 22m simultaneouslywith curing of both the rubber-like material as well as thephenolic-impregnated fabric or cotton 24 so as to effect a mechanicallocking between the Teflon-phenolic liner or preform against rotationinternally relative to the metal sleeve or member 22m. The Teflon orpolytetrafiuoroethylene is threaded and woven relative to a radiallyinner periphery of the fiber or cotton material which is resilientlybacked by the elastomeric material 26 both cured simultaneously. Curingof the rubber or rubber-like material as well as the phenolicsimultaneously in the molding procedure in accordance with the presentinvention accomplishes provision of a bonded rubber to Teflon-phenolicliner and metal outer sleeve rigid externally and internally thoughresilient intermediate thereto together with a resiliently-backedTeflon-lined bearing surface isolated from metal by resilient orelastomeric means 26. As indicated earlier, the polytetrafluoroethylenebearing surface requires no lubrication in service and provides a wearresistant structure which can be formed to have accurate concentricitywith respect to the metal member 22m and any pivot pin (not shown) whichcan be fitted axially and concentrically therein.

FIGURE 3 illustrates the components or parts of a ball joint and socketassembly generally indicated by numeral 30 and in exploded relationrelative to each other. These same parts are shown in assembled relationin FIGURE 4 wherein the same reference numerals are applied. Sequence ofassembly is such that first an elastomeric external dirt seal 30d isaxially fitted over an end of a stud 39s while a cup portion 300 of thedirt seal fits snugly against a partially spherical body portion orsocket 34k provided with an aperture 30a at one end through which thestud 30s projects and opens at an opposite end intermediate laterallyextending flange means 3% Integral with the stud 30s there is a ball orhead portion 30h a periphery of which adjacent to the stud end 30s issuported by an annular bearing surface means 36m including a phenolicbacking for Teflon cloth or threads 3t)! rigidly cured relative to eachother in a shape complementary to the partially spherical ball or headportion Shh.

In accordance with the present invention, there is provided acombination compression seat and bearing surface means indicated bynumeral 32 and specially adapted for use in the ball joint and socketassembly 30. This combination compression seat and surface means ispreferably manufactured in accordance with the proce dure outlined forFIGURE 2 and includes a bearing surface of polytetrafluoroethylenethreads 32t interwoven with one side of a fibrous backing of materialsuch as cotton 32 impregnated with phenolic that is cured simultaneouslywith curing of elastomeric material 32m forced under pressure in asemi-fluid condition into a suitable mold cavity such that a preform ofthe Teflon 32! and fibrous backing 32f is forced against a partiallyspherical portion of a mandrel and then is simultaneously cured with therubber as a resilient backing therefor. An annular sealing lip portion32s extends laterally to one side of the preform and is adapted toengage an inner peripheral surface i of the socket 30z. This annularsealing portion 32s is adapted to protect the bearing surfaces Mr and32t as well as the outer partially spherical periphery of head portion3011 against dust and dirt and also against any spattering of the metalsuch as would be due to welding of the flange portion 309 relative to acomplementary flange portion 34 of a cover 34 provided with a centralaperture 34a. The cover 34 includes an inner arcuate surface 34scomplementary to an upper surface of the combination compression seatand bearing surface means 32 having an upwardly projecting alignmentportion 32z adapted to lit the aperture 34a for properly anchoring thecombination compression seat and bearing surface means 32 in apredetermined position. This anchoring assures proper engagement of theannular sealing lip portion 32s relative to the inner periphery SW ofthe socket for a proper sealing engagement therewith. To enhanceflexibility of the annular sealing lip portion, the elastomeric material32m has an annular recess 321' provided intermediate the inner end ofthe sealing lip portion 32s and the radially outer end of the preformincluding the cotton fabric 32 and Teflon fibers as a bearing surface32t therewith. Simultaneous curing of the elastomeric material andphenolic impregnated relative to the cotton fabric 32) enhances bondingof parts of the combination compression seat and bearing surface means32 relative to each other and assures proper alignment of the sealinglip portion 32s relative to the upper portion or projection 322 as wellas the preform.

The compression seat and bearing surface means 32 serve multiplefunctions including provision of the Teflon bearing surface requiring nolubrication, provision of resiliently compressible spring means in theform of elastomeric material as well as provision of the circumferentialsealing lip as an internal seal to hinder entry of dirt and water intothe joint while in service and entry of weld flash during manufacture.The Teflon bearing surface is backed by a rigid phenolic-impregnatedfabric which is cured and bonded to the rubber or resilient spring in asingle operation. The assembled ball joint with internal and externaldirt seals 39d and 32s, respectively, can be packed with a chassisgrease at assemly and requires no further lubrication for life.Pro-vision of a unitary molded combination compression seat and bearingsurface means 32 including the integral sealing lip portion 32s can bequickly manufactured in a single operation during which resilientmaterial such as rubber and the like is cured and bonded relative to apreform of bearing material including Teflon mechanically woven relativeto a phenolic-backed fibrous material such as cotton curedsimultaneously and bonded relative to the elastomeric material.

FIGURES 4-a and 4-!) illustrate a modification of the combinationcompression seat and bearing surface means 32 to include a plurality ofgrooves 32g preferably in each quadrant extending radially away from thealigning portion 32z along an upper surface of the combination seat andsurface means. The purpose of these four grooves 32g is to reduce thequantity of elastomeric material included in the compression seat suchthat a softer reaction occurs in response to forces transmitted axiallythrough the stud 30s relative to the head portion 30h directly inengagement with the Teflon surface 32f from which shock forces areabsorbed first by the relatively rigid phenolic-cured fabric portion 32integrally bonded and cured relative to the resilient or elastomericmeans. A lower spring rate is realized due to space provided by thesegrooves 32g.

FIGURES 4c, 4d and 4-2 represent further modification of the ball jointand socket means assembly in accordance with the present invention.FIGURE 4c illustrates a plan view of a modified retainer or cover means44 used in place of the cover 34 shown in FIGURES 3 and 4. In theembodiment of views of FIGURES 4-c, 4d and 4e, there is a combinationcompression seat and bearing surface means 42 with an alignment portion421 fitting into an aperture 42a bonded directly relative to a metalinner surface of the retainer or cover 44. The retainer or coverincludes a laterally extending flange portion 44 adapted to be welded orbolted into engagement with the complementary flange portion 3thof thesocket or body portion Stiz and an integral annular sealing lip means42s is also bolted and bonded directly to metal of the cover or retainer44. Also, in accordance with the present invention, the elastomeric orresilient material such as rubber and the like for the combinationcompression seat and bearing surface is cured simultaneously with curingand molding of a preform including a phenolic-impregnated fibrousbacking 42 to which a Teflon fiber surface 421 is mechanically stitched.The molding operation is basically the same as that described in theprocedure with reference to FIGURE 2. FIGURE 4-e illustrates afragmentary enlarged view of the sealing lip portion 42s integral withthe combination compression seat and bearing surface means 42 bondeddirectly to metal of flange portion 44f and cover or retainer 44.

FIGURE 5 illustrates a pivotal joint generally indicated by numeral 50whereby an arm or support means such as in a vehicle suspension systemcan pivot relative to a bracket attached to a frame or vehicle body. Thearm or support means is indicated by numeral 51a and the bracket isindicated by numeral 51b. The bracket includes a laterally extendingannular flange 51 relative to which an annular seal 50s is adapted toabut. The elevational enlarged view of FIGURE 5a illustrated in detailthe abutting portion of the seal that includes a Teflon bearing portion5th adapted to engage an annular surface on one side of the flange 511.This Teflon bearing surface includes a synthetic fiber mechanicallywoven into locking engagement with a matrix or preform including fibrousbacking 50 that is phenolic impregnated and cured as Well as bondedsimultaneously into a unitary structure with resilient material such asrubber and the like of the seal 50s including an end portion Stleadapted to engage a lower annual periphery of the socket S or bodyportion press-fitted into engagement along its outer periphery with aninner surface of the arm or support means 51a having an aperture at oneend thereof. A cap or cover means 500 is welded along its outerperiphery relative to one end 50E of the socket S. The cap is providedwith an apex portion Stlz relative to which a conical end 51c of thebracket 51b extends in axial alignment therewith. A smooth cylindricalmetallic bearing portion 51m is provided between the annular flange 51and the conical end 510. The smooth metal bearing surface 51m projectssubstantially concentrically and axially relative to the socket S fromthe bracket through an open end in the socket adjacent to an annularperiphery thereof engaged by the annular end 50:: of the sealing boot orsealing portion Stis. The socket S as well as a combination compressionseat and bearing surface means generally indicated by numeral 56 ismolded in a procedure such as described with reference to FIGURE 2. Thesocket S is comparable to the metal sleeve member 22m shown in FIGURES 2and 2-a while the combination compression seat and bearing surface means56 includes an elastomeric material 56m cured and molded simultaneouslyand integrally with a preform means including a fibrous backing 56; madeof fiber such as cotton impregnated with phenolic cured simultaneouslvwith the elastomeric material forced in a semi- 0 fluid condition duringmolding against the preform such that a Teflon bearing surface 5drconforms precisely to a mandrel having a diameter comparable to theexternal diameter of the metal bearing surface 511m of the bracket 51b.Since the combination compression seat and bearing surface means 56 ispreferably bonded relative to an inner periphery of metal of socket S,there is a locking of the Teflon bearing surface 561 into apredetermined position relative to the socket. The elastomeric means iscurved and bonded simultaneously with the phenolic-impregnated preformto which the Teflon fiber of the bearing surface 5dr is woven. Aresilient backing is provided for isolation of vibration and noise whichcould be annoying to passengers and also lubrication of the pivot jointis not necessary because the wear resistant Teflon material isresiliently maintained in engagement relative to smooth bearing surfaceSim.

It is to be understood that articles of manufacture can be made inaccordance with the present invention not only by use of injectionmolding procedure but also by use of compression and transfer moldingprocedures such that a preform l4 and the like is urged under hydraulicpressure transmitted through flowable material to conform to mold shapefollowed by simultaneous curing of the material and preform. Duringcompression molding the aperture such as 34a serves as an air escape asflowable material is supplied to the mold. In addition to thermosettingmaterials already noted as surable as backing with the preform, it is tobe understood that various thermoplastic materials can also be used.Examples of the latter include nylon as backing supplied to a mold orpress held closed long enough for phenolic to cure rigid whilesimultaneous cooling also solidifies the thermoplastic material such asnylon into either a flat or curved backing for a bearing surface made inaccordance with the present invention. Nylon is a generic term for anylong-chain synthetic polymeric carbona mide which has recurringcarbonamide groups as an integral part of the main polymer chain andwhich is capable of being formed into a filament in which the structuralelements are oriented in the direction of the axis. Further details asto compositions and characteristics of nylon can be found in US. Patents2,071,250, 2,071,251, 2,071,252, 2,071,253 and 2,130,948.

Another plastic material that can be used is Lexan having a chemicalcomposition of polycarbonate resin and properties which are more fullyset forth in copending application Ser. No. 744-,598-Roode, et al. filedJune 25, 1958 and belong to the assignee of the present invention. Stilla further plastic material that can be used as a backing forphenolic-impregnated fabric interwoven with Teflon is Delrin linearacetal resin. Delrin is a highmelting, highly crystalline polymer ofrepeating CH O groups having an excellent combination of properties suchas high strength, excellent flexural modulus and fatigue life,outsanding resilience and toughness as well as dimensional stabilityunder conditions of high temperature and humidity during an extendedperiod of stress or during exposure to most solvents. Delrin polymer hasvery good abrasion resistance and a relatively low coeflicient offriction.

It is to be noted that a bushing assembly in accordance with the presentinvention can be made by molding structures such as shown by FIGURES 1,1-a and 2a without provision of external metal member 10m, sleeve 22mand the like. In instances where no need for external metal membersexists, then an external sleeve or member need not be bonded as anintegral part.

While the embodiments of the present invention as herein disclosedconstitute preferred forms, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

11. A method for manufacturing a combination compression seat andbearing surface comprising the steps of, placing a cylindrical preformmember having an inner layer of textile fabric interwoven withpolytetrafluoroethylene fibers and an outer concentric layer of fibrousmaterial impregnated with an uncured phenolic resin around acomplementary mold core having a portion of one end threaded and theother end a smooth cylindrical surface located within a mold base,placing an outer cylindrical metal member of a diameter greater thansaid preform member concentrically around said mold core and preformmember, positioning a transfer pot in complementary relationship withsaid mold base, filling the cavity between said outer metal member andsaid preform member with an uncured elastomeric material in a semifluidcondition under sufiicient pressure to force said preform member intointimate contact with said mold core and the contours of said threadedportion, simultaneously curing both said elastomeric material and saidphenolic resin of said fibrous material into a unitary bonded assemblyand unthreading the completed said combination compression seat andbearing surface from said mold core.

2. A bushing insert comprising an internal cylindrical member having aportion of one end threaded and the other end a smooth cylindrical borecomprised of an inner layer of textile fabric havingpolytetrafiuoroethylene fibers woven therein and an outer concentriclayer of phenolic impregnated fibrous material, an outer cylindricalsleeve member of metallic material having a plurality of axially spacedperipheral grooves about the interior surface thereof and a resilientlypliable material securely bonded to the exterior surface of saidcylindrical member including said threaded end portion, whereby saidthreaded end portion prevents relative axial movement between saidcylindrical member and said pliable material,

and completely filling the space between said cylindrical member andsaid outer cylindrical sleeve member including said axially spacedperipheral grooves to form a unitary bonded assembly.

References Cited UNITED STATES PATENTS Re. 24,765 1/1960 White 308-2381,900,298 3/1939 Morris 308-238 X 2,870,295 1/1959 Haroldson 308-238 X2,885,248 5/1959 White.

2,908,532 10/1959 Runton 308-238 2,943,009 6/ 1960 Mirsky.

2,991,808 7/1961 Siegmann 138-141 3,011,219 12/1961 Williams.

3,017,209 1/1962 Thomas.

3,055,788 9/1962 Stonhope 308-238 X 3,082,485 3/1963 Thomas 308-238 X3,089,717 5/1963 Gair 287-93 X 3,094,376 6/1963 Thomas.

3,131,978 5/1964 White 308-238 3,202,749 8/ 1965 White 308-238 X FOREIGNPATENTS 1,181,482 1/1959 France.

MARTIN P. SCHWADRON, Primary Examiner. DAVID J. WILLIAMOWSKY, Examiner.L. L. JOHNSON, Assistant Examiner.

1. A METHOD FOR MANUFACTURING A COMBINATION COMPRESSION SEAT AND BEARINGSURFACE COMPRISING THE STEPS OF, PLACING A CYLINDRICAL PREFORM MEMBERHAVING AN INNER LAYER OF TEXTILE FABRIC INTERWOVEN WITHPOLYTETRAFLUOROETHYLENE FIBERS AND AN OUTER CONCENTRIC LAYER OF FIBROUSMATERIAL IMPREGNATED WITH AN UNCURED PHENOLIC RESIN AROUND ACOMPLEMENTARY MOLD CORE HAVING A PORTION OF ONE END THREADED AND THEOTHER END A SMOOTH CYLINDRICAL SURFACE LOCATED WITHIN A MOLD BASE,PLACING AN OUTER CYLINDRICAL METAL MEMBER OF A DIAMETER GREATER THANSAID PREFORM MEMBER CONCENTRICALLY AROUND SAID MOLD CORE AND PREFORMMEMBER, POSITIONING A TRANSFER POT IN COMPLEMENTARY RELATIONSHIP WITHSAID MOLD BASE, FILLING THE CAVITY BETWEEN SAID OUTER METAL MEMBER ANDSAID PREFORM MEMBER WITH AN UNCURED ELASTOMERIC MATERIAL IN A SEMIFLUIDCONDITION UNDER SUFFICIENT PRESSURE TO FORCE SAID PREFORM MEMBER INTOINTIMATE CONTACT WITH SAID MOLD CORE AND THE CONTOURS OF SAID THREADEDPORTION, SIMULTANEOUSLY CURING BOTH SAID ELASTOMERIC MATERIAL AND SAIDPHENOLIC RESIN OF SAID FIBROUS MATERIAL INTO A UNITARY BONDED ASSEMBLYAND UNTHREADING THE COMPLETED SAID COMBINATION COMPRESSION SEAT ANDBEARING SURFACE FROM SAID MOLD CORE.